In virtualized networks, controllers manage physical forwarding elements to implement logical forwarding elements for logical networks. Controllers compute a desired network state that describes the desired forwarding behaviors for network traffic between the various elements of a logical network. Controllers compute flows to be installed on the managed forwarding elements (MFEs). The installed flows implement the desired network state by updating the actualized network state at the managed forwarding elements.
However, as the flows at the MFEs can be modified by several different controllers, by administrators of the network, etc., it is difficult to maintain a consistent view of the actualized network state and to identify changes that need to be made to the MFEs. In addition, without a consistent view of the desired and actualized network states, failures and disconnects within the network (e.g., when a controller or MFE fails) can cause an excess amount of churn within the network as flows at the MFEs are cleared and re-installed. As managed virtualized networks expand, it becomes increasingly difficult to efficiently manage flows for the various managed forwarding elements within a network system.